In-vitro efficacies of topical microemulsions of clotrimazole and ketoconazole; and in-vivo performance of clotrimazole microemulsion

Topical microemulsions comprising clotrimazole (CTZ) (1%) or ketoconazole (KTZ) (2%), clove oil (6%), tween-20 (25–30%) and aqueous phase (water/buffers) were prepared. Microemulsions were characterized for droplet size, polydispersity, pH value and tested for physical stress and thermodynamic stability. Effective mean diameter of CTZ and KTZ microemulsion droplets ranges between 30 and 50 nm. It was observed that, acidic external phase (pH 1.2, 3.0 and 4.1) for CTZ and KTZ microemulsion requires less emulsifier than the external phase of higher pH (5, 6). Microemulsions were physically stable and there was no substantial change in droplet size or polydispersity under stress condition of centrifugation, freeze-thaw cycle and high temperature. In-vitro efficacy of CTZ and KTZ microemulsions was tested against Candida albicans (ATCC 10231), and was found better than corresponding marketed creams. Microemulsions were found safe and non-irritant when investigated using female Wistar albino rats. In-vivo antifungal efficacy of CTZ microemulsion was studied in rats and compared with its cream. After three days of treatment the scabbing of skin lesion was started, and after five days the scabs became hard and started to erode from the skin. In-vivo observations suggested that CTZ microemulsion can be a successful approach for treatment of topical fungal infection.